"Strength before Weakness"
This is one of my mainstays and I usually repeat it a few times just before a competition. While I am talking of physical strength I'm also speaking to mental fortitude and emotional strength as well. It's very important to me that I have the strength to help others, be that physical strength or otherwise.
"I must not fear, fear is the mind-killer"
Most will recognize this particular litany from the works of Frank Herbert and not Brandon Sanderson. Nevertheless, this is one that gets me through most of my days. The Bene Gesserit litany against fear helps me to realize that what I'm really afraid of is fear itself, fear kills the mind and takes over rational thinking. The litany calls it 'the little death that brings about total obliteration'. You must master your fear otherwise it will master you.